Functional insights into the mode of DNA and ligand binding of the TetR family regulator TylP from Streptomyces fradiae

Content Provider	Scilit
Author	Ray, Shamayeeta Maitra, Anwesha Biswas, Anwesha Panjikar, Santosh Mondal, Jagannath Anand, Ruchi
Copyright Year	2017
Description	Journal: Journal of Biological Chemistry Tetracycline repressors (TetRs) modulate multidrug efflux pathways in several pathogenic bacteria. In Streptomyces, they additionally regulate secondary metabolic pathways like antibiotic production. For instance, in the antibiotic producer Streptomyces fradiae, a layered network of TetRs regulates the levels of the commercially important antibiotic tylosin, with TylP occupying the top of this cascading network. TetRs exist in two functional states, the DNA-bound and the ligand-bound form, which are allosterically regulated. Here, to develop deeper insights into the factors that govern allostery, the crystal structure of TylP was solved to a resolution of 2.3 Å. The structure revealed that TylP possesses several unique features; notably, it harbors a unique C-terminal helix-loop extension that spans the entire length of the structure. This anchor connects the DNA-binding domain (DBD) with the ligand-binding domain (LBD) via a mix of positively charged and hydrogen-bonding interactions. Supporting EMSA studies with a series of ΔC truncated versions show that a systematic deletion of this region results in complete loss of DNA binding. The structure additionally revealed that TylP is markedly different in the orientation of its DBD and LBD architecture and the dimeric geometry from its hypothesized Streptomyces homologue CprB, which is a γ-butyrolactone regulator. Rather, TylP is closer in structural design to macrolide-binding TetRs found in pathogens. Supporting molecular dynamic studies suggested that TylP binds a macrolide intermediate in the tylosin pathway. Collectively, the structure along with corroborating biochemical studies provided insights into the novel mode of regulation of TetRs in antibiotic-producing organisms.
Related Links	http://www.jbc.org/content/292/37/15301.full.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5602390/pdf http://www.jbc.org/article/S0021925820340795/pdf
Ending Page	15311
Page Count	11
Starting Page	15301
ISSN	00219258
e-ISSN	1083351X
DOI	10.1074/jbc.m117.788000
Journal	Journal of Biological Chemistry
Issue Number	37
Volume Number	292
Language	English
Publisher	Elsevier BV
Publisher Date	2017-09-01
Access Restriction	Open
Subject Keyword	Journal: Journal of Biological Chemistry Biochemistry and Molecular Biology C-terminal Extension Dna-binding Protein Tetr Family Regulator X-ray Crystallography Bacterial Metabolism Tylosin Regulation
Content Type	Text
Resource Type	Article
Subject	Cell Biology Biochemistry Molecular Biology